1. Field of the Invention
The invention relates to a method for handling a Hands-Free device, and more particularly to a method for handling a Hands-Free device by an Audio Gateway device with multiple subscriber identity cards.
2. Description of the Related Art
Currently, the Global System for Mobile communication (GSM) standard is the popular standard for mobile phones in the world. The GSM standard, standardized by the European Telecommunication Standards Institute (ETSI) is a cellular network structure and a Time Division Multiple Access (TDMA) system. For a carrier frequency, the TDMA system will divide a frame into eight time slots, wherein each time slot is used to transmit a channel data for a subscriber. In addition, the General Packet Radio Service (GPRS) technology is one of the available technologies of a GSM network. The GPRS technology utilizes the unused channels in the GSM network to provide moderate speed data transmission. The Wideband Code Division Multiple Access (W-CDMA) is a wideband spread-spectrum mobile air interface that utilizes the direct-sequence spread spectrum method of asynchronous code division multiple access to achieve higher data transmission speeds and support more users when compared to the implementation of the time division multiplexing (TDMA) system used by 2G GSM networks. The Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) system is another type of 3G mobile telecommunications standard.
A dual SIM mobile phone is a phone with two or more Subscriber Identity Modules (SIMs), which correspond to different telephone numbers. The dual SIM mobile phone allows a user to use two communication services without carrying two phones at the same time. For example, the same mobile phone may be used for business and private use with separate numbers and bills, thus providing convenience to mobile phone users. Moreover, a hands-free device is an apparatus used with cell phones that permits a user to talk on the phone without holding it. However, it is difficult to handle interactions between the hands-free device and the dual SIMs.